KVM: VMX: Fix DR6 update on #DB exception (8246bf52) · Commits · 戴 / test

According to the SDM, only bits 0-3 of DR6 "may" be cleared by "certain" debug exception. So do update them on #DB exception in KVM, but leave the rest alone, only setting BD and BS in addition to already set bits in DR6. This also aligns us with kvm_vcpu_check_singlestep. Signed-off-by:

Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -4869,7 +4869,8 @@ static int handle_exception(struct kvm_vcpu *vcpu)
	dr6 = vmcs_readl(EXIT_QUALIFICATION);		dr6 = vmcs_readl(EXIT_QUALIFICATION);
	if (!(vcpu->guest_debug &		if (!(vcpu->guest_debug &
	(KVM_GUESTDBG_SINGLESTEP \| KVM_GUESTDBG_USE_HW_BP))) {		(KVM_GUESTDBG_SINGLESTEP \| KVM_GUESTDBG_USE_HW_BP))) {
	vcpu->arch.dr6 = dr6 \| DR6_FIXED_1;		vcpu->arch.dr6 &= ~15;
			vcpu->arch.dr6 \|= dr6;
	kvm_queue_exception(vcpu, DB_VECTOR);		kvm_queue_exception(vcpu, DB_VECTOR);
	return 1;		return 1;
	}		}

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